parseInt() vs. Unary Plus: Which Should You Use for Number Conversion?

parseInt vs. Unary Plus: A Comprehensive Comparison

To understand the nuances between parseInt() and the unary plus operator ( ), let's delve into their distinct functionality and performance characteristics.

Conversion Mechanics:

• parseInt(): Parses a string and converts it to an integer, optionally specifying a base (radix). For non-numeric strings, it returns NaN.
• Unary Plus: Coerces a value to a number. While it can convert numeric strings to numbers, it also coerces booleans, null, and undefined to numbers (e.g., true becomes 1).

Performance:

Performance benchmarks show that parseInt() is slower than the unary plus operator, especially in Node.js (see jsPerf test mentioned). This is because parseInt() involves a complex parsing process, while the unary plus operator performs a simple coercion.

Fallback Behavior:

In cases where the input is not a numeric value, both parseInt() and the unary plus operator return NaN.

When to Use parseInt():

When you specifically need an integer result and want to control the input base, parseInt() is the preferred choice. For example, if you are parsing a hex string or a decimal string with a specific radix.

When to Use Unary Plus:

For general numeric conversion where you want to coerce a value of any type into a number, the unary plus operator is more efficient and flexible. It handles booleans, null, undefined, and strings that can be parsed as numbers.

Double Tilde Operator ~~:

The double tilde operator (~~) is primarily used to perform bitwise negation (e.g., ~~x negates the bits of x). It has no specific role in numeric conversion and is generally not recommended for that purpose.

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